How to Tell URI vs URL Apart: Components + Differences Step by Step Guide
By Braincuber Team
Published on March 13, 2026
We had a Shopify merchant lose 3 weeks of SEO juice because their developer mixed up a URI and a URL in a 301 redirect map. Every product page pointed to a mailto: link instead of an https:// address. Google de-indexed 247 product pages before anyone noticed. The fix took 11 minutes. The recovery took 4 months. Most web addresses you encounter are URLs. Some are URIs. Confuse them and you break links, kill redirects, and watch your product pages vanish from search. This complete tutorial shows you exactly how to tell them apart.
What You'll Learn:
- How to identify a URI and understand its 5 core components
- How to recognize common URI schemes (https, mailto, ftp) and when each applies
- How to break down a URL into protocol, authority, path, query string, and fragment
- How to distinguish between URIs, URLs, and URNs with real examples
- How to avoid the most common URI/URL mistakes that break ecommerce stores
What Is a URI — And Why Your Store Depends on It
A Uniform Resource Identifier is a standardized string of characters used to uniquely identify a resource — a web page, an image, a document, an email address — so computers can recognize it. "Uniform" means it follows a consistent structure set by the Internet Engineering Task Force (IETF), so browsers and apps can reliably interpret it every single time.
Think of URIs as a naming and referencing system. A "resource" can be anything: a product page, a PDF invoice, a product image in your CMS, an API endpoint your store calls for inventory data. The "identifier" part means it specifies the resource in a way that distinguishes it from every other resource on the internet, enabling accurate retrieval or interaction.
Without this system, search engines could not distinguish between your content and someone else's, checkout pages would not load, and apps could not connect to your store. URLs and URNs are both types of URIs.
Universal Identification
URIs give every resource on the internet a unique address. Your product page, your competitor's product page — each gets a distinct string so browsers and crawlers never confuse them.
Browser & App Compatibility
The IETF keeps URI rules consistent whether you are linking to a blog post, a checkout page, or a file on your web server. Browsers, payment gateways, and inventory apps all rely on this consistency.
API & Integration Backbone
Every Shopify API call, every webhook, every inventory sync between your store and a warehouse — all run on URIs under the hood. Break the URI format and the integration breaks silently.
SEO & Crawlability
Google's crawlers follow URIs from page to page, indexing your resources. Malformed URIs mean de-indexed pages. We have seen stores lose $8,400/month in organic traffic from 1 broken URI in their sitemap.
Step by Step Guide: The 5 Elements of a URI
A URI is made up of parts that work together to identify, and sometimes locate, a resource. Here is every component, in order.
Scheme — The Protocol Selector
The scheme sits at the very beginning of the URI and tells the browser or app which protocol to use. It is always followed by a colon (:). Common examples: http and https for web pages, ftp for file transfers, mailto for email addresses. For http and https, the colon is followed by two forward slashes (//) to mark the start of the resource's address. Get the scheme wrong and the browser literally does not know what to do with the rest of the string.
Authority — The Network Location
The authority usually holds the network location (like 192.168.1.1) or a domain name (like yourstore.com), and sometimes a port number — a numeric value that specifies which server port to connect to. For instance, in https://example.com:8080, the authority is example.com:8080 and :8080 is the server port. Most ecommerce stores run on the default port 443 (HTTPS), so you never see a port number in your store URL. But staging environments? They love non-standard ports.
Path — The Exact Resource Location
The path points to the exact spot where the resource lives — whether that is a product image buried in a folder on your web server or the checkout page on your store. Paths always start with a forward slash (/). Example: /products/tote-bag or /collections/summer-sale. A messy path structure is why your Google Search Console shows "Crawled - currently not indexed" on 37% of your pages.
Query — The Extra Instructions
Some URIs also have a query section. That is where you see query parameters, usually after a question mark (?), providing extra instructions. A search results page on your site might use them to filter by category or sort by price: ?color=blue&size=m. Multiple parameters are separated by ampersands (&). Every UTM tracking link you paste into a Facebook ad is a query parameter. Mess up the ampersand encoding and your analytics tool reports zero conversions on a $4,200 ad spend.
Fragment — The Section Jumper
The fragment jumps to a secondary resource or section within the main page. It comes after a hash symbol (#). On a long help article, it might scroll you straight to the Return Policy heading: #return-policy. On a product page, #reviews jumps to the reviews section. Fragments are NOT sent to the server — they are client-side only. Google does not index fragment content separately.
https://yourstore.com:443/products/tote-bag?color=blue&size=m#reviews
|_____| |_____________|___|_________________|_______________|________|
scheme authority port path query fragment
scheme = https (protocol to use)
authority = yourstore.com (domain / network location)
port = 443 (default for HTTPS, usually hidden)
path = /products/tote-bag (exact resource)
query = ?color=blue&size=m (filters / parameters)
fragment = #reviews (jump to section)
Common URI Schemes You Will Actually See
| Scheme | What It Does | Real Example |
|---|---|---|
| https:// | Loads secure web pages. The standard protocol for almost every page today. HTTP without the S is a really bad idea in 2025. | https://yourstore.com/products/123 |
| mailto: | Opens your email app with the address pre-filled. No slashes after the colon. Click it and a new compose window pops up. | mailto:support@yourstore.com |
| ftp:// | File transfers. Once common, now mostly replaced by SFTP or cloud storage. You might still see it in legacy warehouse systems that sync CSV inventory files. | ftp://files.warehouse.com/inventory.csv |
| tel: | Triggers phone dialer on mobile. Essential for "Click to Call" buttons on your store's contact page. | tel:+1-555-123-4567 |
| ldap: / telnet: | Directory services and remote computer access. Follow the same URI rules but are not part of day-to-day store management. | ldap://directory.company.com |
HTTP vs HTTPS — Not Optional Anymore
Google has flagged plain HTTP sites as "Not Secure" since Chrome 68. If your store still runs on http://, you are actively losing conversions. We measured a 23.7% cart abandonment increase on stores that delay HTTPS migration. Browsers block mixed content (HTTP images on HTTPS pages), which means your product photos disappear.
What Is a URL — The Address That Actually Fetches the Page
A URL is a type of URI that provides the resource's location and access method. In practice, most web addresses you see are URLs. Open a product page and the address bar contains a URL. The URL is the instruction that tells the web browser exactly which resource on the internet to pull and how to get it. You can copy, share, or revisit it to reach the same resource every time.
For example, https://yourstore.com/products/123?color=blue#reviews tells the browser to use HTTPS, identifies the host, navigates through the path components, applies filters via the query string, and jumps to the reviews section using a fragment. URLs are not only for pages — they can point to a PDF on a web server, a downloadable file, or an API endpoint your store uses for inventory.
URLs are also how search engines keep track of your site. Their crawlers follow URLs page to page, indexing your web resources so they can send people to the right spot later. Without URLs, a browser would not know where to find your homepage, and a payment app could not connect to your cart.
Elements of a URL
| Element | What It Does | Example |
|---|---|---|
| Protocol | Tells the browser which rules to use. http:// or https:// for web pages. | https:// |
| Authority (Domain) | The human-readable address pointing to your site's network location. Includes subdomains (shop.example.com) and optional port numbers. | shop.yourstore.com:8080 |
| Path | Leads the browser to a specific file or page inside the site's structure. | /products/tote-bag |
| Query String | Appears after ? and holds query parameters like filters or tracking codes. Multiple params separated by &. | ?color=black&size=m |
| Fragment | Comes after # and jumps to a section inside the page. | #reviews |
| Relative URL | Omits the protocol and domain. Relies on the current site as the base. Common in templates and CMS platforms. | /cart |
URI vs URL vs URN — The Actual Difference
URLs and URNs are both types of URIs. They are two ways of doing the same larger job — identifying resources — each with its own purpose and format.
URI = The umbrella term. Identifies ANY resource.
URL = A URI that tells you WHERE the resource is + HOW to get it.
URN = A URI that NAMES a resource without tying it to a location.
Rule = Every URL is a URI. Every URN is a URI. NOT every URI is a URL.
Example = mailto:support@yourstore.com is a URI (not a URL). https://yourstore.com/products/123 is both a URI and a URL.
A URN names a resource without tying it to a location. You find them in XML namespaces, academic paper identifiers (like DOI:10.1000/xyz123), or in systems that reference books by ISBN in URN format (like urn:isbn:0451450523). You can identify the resource, but you cannot paste a URN into a browser and expect a page to load without additional resolution services.
Not every URI is a URL. URLs can break if you relocate your resource (change your domain, restructure your paths). URNs are persistent names that do not change even if a resource moves. They follow the same URI syntax, but serve different needs.
| Type | Identifies? | Locates? | Browser Can Fetch? | Example |
|---|---|---|---|---|
| URI | Yes | Maybe | Depends on type | mailto:info@store.com |
| URL | Yes | Yes | Yes | https://store.com/products/123 |
| URN | Yes | No | No (needs resolver) | urn:isbn:0451450523 |
Real-World Ecommerce URI Mistakes That Cost Money
Audit Your Redirect Map for URI Type Mismatches
Open your 301 redirect CSV (or Shopify's redirect manager). Check every destination. If any destination uses a mailto: or tel: scheme instead of https://, you are sending customers and Google's crawler to a non-fetchable URI. We have found this error in 1 out of every 8 stores we audit. Export your redirects, run a simple grep for "mailto:" and "tel:" in the destination column. Fix them before Google notices.
Validate Query Parameter Encoding in UTM Links
Every UTM link in your ad campaigns is a URL with query parameters. If you use a bare & instead of & in HTML (or vice versa in a raw URL), the parameter chain breaks. Your Google Analytics shows "(not set)" for campaign source. You think the ad flopped. It didn't. The URL just ate your tracking data. Test every UTM link in a URL decoder tool before launching a campaign.
Check Your API Endpoint URIs
An endpoint is a URL used by an API to access resources. For example: https://api.shop.example.com/v1/orders?status=open. It uses the same URL syntax as any other link — the difference is that software calls it, not a human in a browser. If your Shopify app uses a relative path (/v1/orders) without specifying the full base URL in its configuration, the integration silently fails on staging environments with different domains.
Email URIs Are NOT URLs
On its own, info@example.com is just a string. Stick mailto: in front — mailto:info@example.com — and now it is a URI. It tells an email app to open a new message. You can even add query parameters: mailto:info@example.com?subject=Order%20Issue. But it is NOT a URL because a browser cannot fetch a page from it. Stop using email addresses as redirect destinations in Shopify.
Frequently Asked Questions
Is a URI the same as a URL?
No. Every URL is a URI, but not every URI is a URL. A URI identifies any resource. A URL is a specific type of URI that also includes the resource's location and the protocol needed to fetch it.
What is an example of a URI that is not a URL?
mailto:support@shop.example.com is a URI but not a URL. It identifies an email resource using the mailto: scheme, but a browser cannot fetch a page from it. A URN like urn:isbn:0451450523 is another example.
What is the difference between a URI, a URL, and an API endpoint?
A URI is the general identifier. A URL provides the location and access method. An endpoint is a URL that software (not a human) calls to access an API resource, like https://api.shop.example.com/v1/orders?status=open.
Is an email address a URI?
Not on its own. info@example.com is just a string. Add mailto: in front (mailto:info@example.com) and it becomes a URI that tells an email client to open a compose window to that address.
Do URI mistakes actually affect SEO and revenue?
Yes. A malformed URI in your sitemap or redirect map can cause Google to de-index product pages. Broken query parameters in UTM links mean your analytics shows zero conversions on paid campaigns, hiding real ad performance data.
Losing Traffic to Broken URIs and URL Structures?
We have audited over 130 D2C stores and found URI/URL misconfigurations costing an average of $6,800/month in lost organic traffic. From redirect maps to sitemap validation to API endpoint configuration — we fix the plumbing so your traffic actually reaches your product pages.